The present invention relates to gluing or bonding systems for door seals, and more particularly to systems for adhesively bonding door seals to door flanges of automobiles.
The present invention relates to a gluing system for auxiliary door seals which are to be adhesively bonded onto a door flange of an automotive vehicle. The gluing system serves to prepare the auxiliary door seal for the bonding operation proper by fixing a door seal by means of a vacuum onto a mounting template and by providing the door seal at both end sections with a viscous adhesive, in addition to the dry adhesive strip already placed on said seal, after the adhesive application portion has been activated by atmospheric plasma treatment.
It is the object of the present invention to provide a gluing system with which the above-mentioned working steps are automatically performed, and it should here be ensured that exactly determined small amounts of the adhesive are applied to the door seal at exactly observed places which have previously been subjected to plasma irradiation.
This object is achieved according to the invention by the features of patent claim 1.
Advantageous developments of the invention are characterized in the subclaims.
The bonding system according to the invention contains a receiving means for detachably holding a vacuum-type mounting template in which a plurality of spaced-apart trough-like suction members of a rubber-like material are arranged on a peripheral edge at the narrow side, the suction members being connectable via a joint line and a connection valve to a vacuum source of the bonding system. These suction members preferably suck an auxiliary door seal placed by hand on the peripheral edge, the seal being thereby fixed onto the mounting template. The mounting template further contains a relief valve which is connected to the line and by the actuation of which, preferably by pressing an actuation pin inwards, the vacuum is eliminated, so that the auxiliary door seal is released, which takes place in a subsequent working step, namely after the auxiliary door seal has been adhesively bonded to the door flange of an automotive vehicle.
The bonding system according to the invention further includes a slide means by which the receiving means with the mounting template clamped thereonto and the auxiliary door seal fixed thereto is passed below preferably two plasma irradiation means which irradiate the end portions of the auxiliary door seal which are intended for the application of a viscous adhesive, preferably a one-component adhesive. The slide means transports the mounting template with the auxiliary door seal onwards below two metering devices, each of which applies a predetermined amount of a viscous adhesive to the auxiliary door seals. The mounting template with the auxiliary door seal is lifted by a lifting means of the slide means to the outlet opening of the metering device. The resulting adhesive thread is torn off in a subsequent lowering step.
The slide means is preferably conveyed by its drive means at a constant speed from the initial position into the end position below the metering devices and back again. When the initial position has been reached again, the mounting template with the auxiliary door seal which is fixed thereto and provided with the activated adhesive is taken from the receiving means, whereupon the auxiliary door seal is adhesively bonded by means of the mounting template to the predetermined location of the door flange of an automotive vehicle and is released from the mounting template after the vacuum has been eliminated. The template is then again detachably fastened to the receiving means of the bonding system according to the invention, the vacuum unit which is in permanent operation being automatically connected to the suction members.
Since the area of the door flange to which the auxiliary door seal is adhesively bonded by means of the manually operated mounting template is not flat, but extends in slightly curved fashion, different mounting templates must be used for applying the auxiliary door seals to the left and right door of an automotive vehicle, and the peripheral edges of the mounting templates which receive the auxiliary door seal extend here in mirror-inverted fashion relative to each other. To handle both types of mounting templates in the inventive bonding system without the need for newly adjusting e.g. the slide means, it is suggested according to a further essential aspect of the invention that each mounting template should include a section which is positioned on a straight connection between the bonding points. With such a section the mounting template is mounted on the fastening means of the receiving means, e.g. in a clamping means.
With such a configuration the slide means transports the bonding points into the exactly predetermined position below the two metering devices in both types of mounting templatesxe2x80x94for the left and right vehicle door, so that the preferably very small amount of adhesive which may e.g. be 0.01 cm3 is exactly applied to the predetermined locations.
In a further development the mounting template may have a section which is the lower one in the installation position of the bonding system and extends in straight fashion over the entire length thereof and on which the curved upper section is located with the peripheral edge receiving the auxiliary door seal. The mounting template may here be made integral from a plastic material. The connection valve projects from the bottom side of the mounting template at an end section for connection to the source of vacuum, and the relief valve from the other end section.
It is not only indispensable that the auxiliary door seals must be provided with adhesive exactly at the predetermined places (which need not necessarily be located on the end sections of the auxiliary door seal and the number of which is of course not limited to two), but the adhesive must be applied in an exactly observed predetermined amount which is very small in the case of the auxiliary door seal.
To solve this problem, the invention suggests that each metering device provided in the bonding system should contain a cartridge including the adhesive, which is connectable via a valve means to a displacement-type metering means, and that the valve means should contain a double seat valve which releases either the connection between the cartridge and the displacement-type metering means or the connection between the displacement-type metering means and the valve outlet opening.
Furthermore, the cartridge is here preferably engaged by a pneumatic piston which generates the pressure required for transferring the adhesive into the displacement-type metering means, and the displacement-type metering means contains a pneumatic piston/cylinder unit whose piston is displacement-controlled, whereby an exactly defined amount of adhesive is ejected. The initial position of the piston in the cylinder is preferably adjustable.
In the metering device according to the invention, whenever the double seat valve thereof closes the valve outlet opening of the metering device, the interior of the cartridge communicates with the cylinder of the displacement-type metering device to always fill again the cylinder chamber before the piston returns into the initial position. When the double seat valve is moved into the lifted position in which the valve outlet opening is released, a preferably conical section of the valve needle closes a correspondingly shaped valve seat, thereby interrupting the connection between the cartridge and the displacement-type metering means, whereupon the pneumatic piston of the displacement-type metering means is pushed forwards up to its exactly predetermined end position and ejects the intended amount of adhesive.
The reciprocating valve needle preferably comprises a ball-shaped valve needle head which can cooperate with a correspondingly shaped valve seat to close the valve outlet opening. In the rear upper position, a conical section of the valve needle hits, as mentioned above, upon a correspondingly shaped valve seat.
The position of the pneumatic piston which is seated in the cartridge is expediently monitored, and when a minimum level is reached, it should be indicated that a new filled cartridge has to be inserted.
While the metering device of the invention has been described in connection with the bonding system of the invention, it should be noted that said metering device is suited not only for ejecting an adhesive, but for discharging generally low- to high-viscosity substances, such as fats or the like. Thus the metering device constitutes an independent invention which is particularly suited for the exact application of minimum amounts of a viscous substance.